JP2008-218204A discloses a multipoint spark plug having main body fitting that is inserted into a plug hole of a cylinder head so that a tip end portion thereof opposes a combustion chamber, and a positive electrode, an intermediate electrode, and an earth electrode that are held by an insulating portion and project into the combustion chamber from the insulating portion so as to form a plurality of ignition gaps. In this multipoint spark plug, a heat range can be set by adjusting the depth of a recession formed in a tip end of the insulating portion so as to alter a surface area of the insulating portion that is within the combustion chamber.